Mastodonwhales are mythic animals. Sailors from all over the world heard stories of them, but no one had ever seen them. Gigantic whales, floating in a quasi lethargy at the heart of warm seas, their back covered with soil. a luxurious vegetation develops there, even protecting savage wildlife, camouflaged as small archipelagos. But once every generation, the Mastodonwhales go on their last voyage towards the frozen waters which saw their birth, to reproduce and die there.